import 'dart:convert';

import 'package:shared_preferences/shared_preferences.dart';

///SharedPreferences 工具类
class SpUtils {
  ///创建工厂方法
  static SpUtils? _singleton;

  factory SpUtils() => _singleton ??= SpUtils._initial();

  static SharedPreferences? _prefs;

//创建命名构造函数
  SpUtils._initial() {
    //为什么在这里需要新写init方法 主要是在命名构造中不能使用async/await
    init();
  }

  //初始化SharedPreferences
  void init() async {
    _prefs ??= await SharedPreferences.getInstance();
  }

  //到这里还没有完 有时候会遇到使用时提示 SharedPreferences 未初始化,所以还需要提供一个static 的方法
  static Future<SpUtils?> perInit() async {
    if (_singleton == null) {
      //静态方法不能访问非静态变量所以需要创建变量再通过方法赋值回去
      SharedPreferences preferences = await SharedPreferences.getInstance();
      _singleton = SpUtils._pre(preferences);
    }
    return _singleton;
  }

  SpUtils._pre(SharedPreferences prefs) {
    _prefs = prefs;
  }

  /// put object.
  static Future<bool>? putObject(String key, Object value) {
    return _prefs?.setString(key, json.encode(value));
  }

  /// get obj.
  static T? getObj<T>(String key, T f(Map v), {T? defValue}) {
    Map? map = getObject(key);
    return map == null ? defValue : f(map);
  }

  /// get object.
  static Map? getObject(String key) {
    String? _data = _prefs?.getString(key);
    return (_data == null || _data.isEmpty) ? null : json.decode(_data);
  }

  /// put object list.
  static Future<bool>? putObjectList(String key, List<Object> list) {
    List<String>? _dataList = list.map((value) {
      return json.encode(value);
    }).toList();
    return _prefs?.setStringList(key, _dataList);
  }

  /// get obj list.
  static List<T>? getObjList<T>(String key, T f(Map v),
      {List<T>? defValue = const []}) {
    List<Map>? dataList = getObjectList(key);
    List<T>? list = dataList?.map((value) {
      return f(value);
    }).toList();
    return list ?? defValue;
  }

  /// get object list.
  static List<Map>? getObjectList(String key) {
    List<String>? dataLis = _prefs?.getStringList(key);
    return dataLis?.map((value) {
      Map _dataMap = json.decode(value);
      return _dataMap;
    }).toList();
  }

  /// get string.
  static String? getString(String key, {String? defValue = ''}) {
    return _prefs?.getString(key) ?? defValue;
  }

  /// put string.
  static Future<bool>? putString(String key, String value) {
    return _prefs?.setString(key, value);
  }

  /// get bool.
  static bool? getBool(String key, {bool? defValue = false}) {
    return _prefs?.getBool(key) ?? defValue;
  }

  /// put bool.
  static Future<bool>? putBool(String key, bool value) {
    return _prefs?.setBool(key, value);
  }

  /// get int.
  static int? getInt(String key, {int? defValue = 0}) {
    return _prefs?.getInt(key) ?? defValue;
  }

  /// put int.
  static Future<bool>? putInt(String key, int value) {
    return _prefs?.setInt(key, value);
  }

  /// get double.
  static double? getDouble(String key, {double? defValue = 0.0}) {
    return _prefs?.getDouble(key) ?? defValue;
  }

  /// put double.
  static Future<bool>? putDouble(String key, double value) {
    return _prefs?.setDouble(key, value);
  }

  /// get string list.
  static List<String>? getStringList(String key,
      {List<String>? defValue = const []}) {
    return _prefs?.getStringList(key) ?? defValue;
  }

  /// put string list.
  static Future<bool>? putStringList(String key, List<String> value) {
    return _prefs?.setStringList(key, value);
  }

  /// get dynamic.
  static dynamic getDynamic(String key, {Object? defValue}) {
    return _prefs?.get(key) ?? defValue;
  }

  /// have key.
  static bool? haveKey(String key) {
    return _prefs?.getKeys().contains(key);
  }

  /// contains Key.
  static bool? containsKey(String key) {
    return _prefs?.containsKey(key);
  }

  /// get keys.
  static Set<String>? getKeys() {
    return _prefs?.getKeys();
  }

  /// remove.
  static Future<bool>? remove(String key) {
    return _prefs?.remove(key);
  }

  /// clear.
  static Future<bool>? clear() {
    return _prefs?.clear();
  }

  /// Fetches the latest values from the host platform.
  static Future<void>? reload() {
    return _prefs?.reload();
  }

  ///Sp is initialized.
  static bool isInitialized() {
    return _prefs != null;
  }

  /// get Sp.
  static SharedPreferences? getSp() {
    return _prefs;
  }
}
